FILE - In this Jan. 26, 2013 file photo, a bar code is seen attached to a marijuana plant at a grow house in Denver. The bar codes are assigned to each plant and follow it through the growing and distribution process. Eight former Drug Enforcement Administration chiefs say the federal government needs to act now or it might lose the chance to nullify Colorado and Washington's laws legalizing recreational marijuana use. The onetime DEA heads plan to issue joint statements Tuesday, March 5, 2013, saying the Obama administration has reacted too slowly and should immediately sue to force the states to rescind the legislation. (AP Photo/Ed Andrieski, File)